1. Field of the Invention
This invention relates to containers for the bulk storage and shipment of materials. More particularly, the invention relates to a corrugated paperboard bulk box with set-up assisting features, a locking bottom flap construction, and a smooth interior surface.
2. Prior Art
In the bulk handling of materials, e.g., bulk resins, fruit juices, tomato paste, meat, fresh produce, etc., containers of relatively large size are commonly used to transport and store the material. These containers must be capable of withstanding the weight of the contents, as well as the rough handling to which they may be subjected. Further, they should be relatively easy to set up, and capable of being stacked on top of one another, and of being handled with mechanized equipment. In addition, it is sometimes desirable or necessary to place a flexible bag liner inside the box, especially for the handling of fluid materials.
A variety of containers have been developed in the prior art to meet these criteria, including metal drums, plywood bins and corrugated paperboard boxes. While metal drums and plywood bins possess the requisite strength and durability, they are expensive to manufacture, store and ship. Corrugated paperboard boxes are less costly to make, and generally can be collapsed for compact storage and shipment. However, they may be difficult to set up, and/or may not be capable of withstanding rough handling, and/or may have elements protruding into the interior of the box, exposing the liner to potential damage from such protrusions.
Accordingly, there is a need for a bulk container which is inexpensive to make and use, is strong and durable, may be collapsed for compact storage and shipment, is easy to set up, and which has a smooth interior surface.
The present invention comprises a bulk container which is strong and durable, which may be collapsed for compact storage and shipment, which may be set up quickly and easily, and which has a smooth interior surface.
The container of the invention preferably is made of corrugated paperboard having adequate strength to withstand the weight of the contents and to enable multiple containers to be stacked on top of one another. It is also capable of being palletized so that it can be efficiently handled with mechanized equipment. The container can be collapsed for compact storage, and has a simplified locking bottom flap construction that is quick and easy to set up and is durable even when subjected to rough handling. The container of the invention also has aligning means which facilitates positioning and squaring up of the container during set up, and which holds it in that position after it is set up.
In a preferred embodiment, the container of the invention is an octagonal corrugated paperboard box having opposed pairs of parallel side walls and diagonal corner panels. Opposed pairs of major and minor bottom flaps are foldably joined along score lines at one edge to respective pairs of opposed side walls, and have opposite free edges.
The locking bottom flap construction includes a notch or cut-out in the free edge of each of the minor flaps, and a T-shaped central locking tab in the free edge of one of the major flaps. When the flaps are folded inwardly toward one another to close the bottom of the box, the free edges of the major flaps meet in flush, abutting relationship, with an end portion of the locking tab lying against the adjacent edge of the opposed bottom flap. The minor flaps overlie the major flaps and the locking tab, with the notches in the free edges of the minor flaps in registry with the locking tab.
The T-shaped locking tab has bendable arms protruding from opposite sides of its free end, whereby the free end of the tab may be grasped and pulled through the opening formed by the notches in the confronting edges of the minor flaps, whereby the arms engage against the confronting edges of the minor flaps to hold or lock the flaps in their inwardly folded position.
This structure presents a smooth interior bottom surface, with no protrusions extending into the box that might pose a risk of chafing or puncturing of a flexible bag liner placed in the box.
Further, the major flaps include side portions extending in alignment with and cut from the bottom ends of the associated diagonal corner panels, so that when the major flaps are folded inwardly over the bottom of the box, the corners of the side portions project beyond the diagonal corner panels to define fastening tabs that may be used to secure the box to a pallet.
The aligning means includes a pair of spaced apart slots at the score line joining each minor bottom flap to its associated side wall, and a small tab projecting outwardly from the side edge of each of the side portions of the major bottom flaps. The tabs project into the slots to position and square-up the box and hold it in this position as the box is being set up and after the box is set up. More specifically, during set up of the box the minor flaps, or at least one of them, are in generally coplanar relationship with its associated side wall, and the major flaps, or at least one of them, are then folded inwardly over the bottom of the box, sweeping the tab along the surface of an adjacent minor flap until the tab comes into registry with the slot, whereupon the tab projects into the slot to hold the major flap in this folded position. After both major flaps are thus folded, the minor flaps are folded inwardly over the major flaps, and the locking tab engaged. The location of the tabs and slots is such that when they are interengaged the box is properly aligned and squared.
When the major flaps and then the minor flaps are folded inwardly over the bottom of the box into overlying relationship with one another, it is necessary only to pull the T-shaped locking tab outwardly to cause the tab to flex and move through the opening formed by the notches in the confronting edges of the minor bottom flaps, whereupon the arms or wings of the xe2x80x9cTxe2x80x9d expand or spring outwardly to engage behind the bottom flaps to lock the tab, and thus the bottom flaps, in closed position. The bottom flaps are thereby securely interlocked with one another to form a strong closed bottom that remains in its erected condition even when the box is roughly handled.
The corners of the arms are rounded to eliminate the potential for the T-shaped tab to get caught or snagged on any other edge and be tom. The arms are partially defined by diagonal scores which cause the arms to bend in the appropriate location and eliminate tearing. Further, by facilitating bending of the arms in the appropriate manner, the durability of the locking tab is increased, enabling it to last through many cycles of use.
Means may also be provided in the sidewalls for locking cooperation with a closure cap or cover to be fitted over the top end of the box. In one embodiment, this
means comprises openings formed through at least a pair of opposed side walls near the top end thereof for cooperation with the tabs on the cover.
Although the preferred embodiment is an octagonal or eight-sided box, it should be understood that the invention may be adapted to other polygonal shapes, such as a four-sided or ten-sided box, for example. Further, the box of the invention may comprise any suitable flute construction, including AA, CA, BC, etc., depending upon the desired properties. Moreover, a moisture resistant adhesive may be used in the manufacture of the box, which may additionally be treated with a suitable commercially available moisture resistant material. Further, if desired, a liner may be placed inside the box. The liner and the box may each comprise one-piece triple wall constructions laminated together.
The bottom flap construction with flush, abutting flap edges and a locking tab structure that does not extend or protrude into the interior of the box, may be used with or without the aligning feature. Further, in applications which do not require the outside (major) flaps to be held in the closed position, the die-cut bottom style of the invention can be used without the T-shaped locking tab.